Production of hydrocarbons from a well requires many different steps as well as an assortment of tools and chemicals. Common chemicals include fracturing fluids, viscosity breakers and scale inhibiting compounds. Effective use of these fluids requires an understanding of their chemical and physical characteristics. Frequently, successful economic well completion requires an accurate and continuous determination of fluid density. In particular, xe2x80x9creal timexe2x80x9d knowledge of fluid density can significantly reduce completion costs.
Typical instruments for determining fluid density include gradiomanometers and nuclear fluid density type tools. Although adequate for the purpose, neither instrument completely meets industry""s needs. Readings from gradiomanometers are affected by turbulence and otherwise subject to deviation. Nuclear fluid density tools use a chemical gamma-ray source positioned with respect to a gamma-ray detector. Fluid passing between the gamma-ray source and detector absorbs gamma-rays. Thus a high radiation count indicates a low fluid density, while a low count indicates high fluid density. Nuclear fluid density tools provide suitable results; however, the use of a radioactive source creates safety and environmental concerns. Therefore, the ability to accurately measure the density of a flowing fluid without turbulence induced error or the use of radioactive material would be beneficial to the well completion industry.
The current invention provides an apparatus for determining the density of a flowing fluid. The apparatus comprises two pressure assessment zones. Each pressure assessment zone carries at least one pair of pressure sensing points. Typically, the first pressure assessment zone has an angle of inclination ranging from about 10xc2x0 to about 90xc2x0 or from about xe2x88x9210xc2x0 to about xe2x88x9290xc2x0 from horizontal and the second pressure assessment zone preferably has an identical angle of inclination. Preferably, the pressure assessment zones carrying the pressures sensing points have identical interior diameters.
The present invention also provides an apparatus for continuously determining the density of a flowing fluid. The apparatus for continuously determining the density of a flowing fluid comprises two pressure assessment zones joined in fluid communication. Each pressure assessment zone carries at least one pair of pressure sensing points. Typically, the first pressure assessment zone has an angle of inclination from about 10xc2x0 to about 90xc2x0 or from about xe2x88x9210xc2x0 to about xe2x88x9290xc2x0 from horizontal and the second pressure assessment zone preferably has an identical angle of inclination. Preferably, the pressure assessment zones carrying pressures sensing points have identical interior diameters. The pressure assessment zones carrying the pressure sensing points may optionally contain fluid flow straighteners. The pressure sensing points either transmit fluid pressure to a pressure sensor or designate the attachment point for the pressure sensor. To generate continuous, real time results, the pressure sensor is linked to a central processing unit, such as a personal computer, capable of continuously calculating the density of the fluid passing through the pressure assessment zones.
Additionally, the current invention provides a method for determining the density of a flowing fluid. The method passes the fluid either upward or downward through a first pressure assessment zone and measures fluid pressure as it passes through the first pressure assessment zone. Subsequently, the method passes the fluid in the opposite direction through a second pressure assessment zone and measures fluid pressure as it passes through the second pressure assessment zone. The method then calculates fluid density based on the pressure readings obtained from each pressure assessment zone.
The current invention also provides another method for determining the density of a flowing fluid. The method initially passes the fluid through a first pressure assessment zone at an angle between about 10xc2x0 and 90xc2x0 or between about xe2x88x9210xc2x0 and xe2x88x9290xc2x0 from horizontal. Subsequently, the fluid passes through a second pressure assessment zone at an angle identical to the first pressure assessment zone; however, the fluid flows in the opposite direction through the second pressure assessment zone. The method determines fluid pressure in each pressure assessment zone and calculates the density of the fluid.
Further, the current invention provides yet another method for continuously calculating the density of a flowing fluid. The method initially passes the fluid through a first pressure assessment zone at an angle between about 10xc2x0 and 90xc2x0 or between about xe2x88x9210xc2x0 and xe2x88x9290xc2x0 from horizontal. Subsequently, the fluid passes through a second pressure assessment zone at an angle identical to the first pressure assessment zone; however, the fluid flows in the opposite direction through the second pressure assessment zone. Thus, if the fluid flows upward through the first pressure assessment zone, then it will flow downward through the second pressure assessment zone. The method continuously determines the pressure in each pressure assessment zone and communicates the pressure readings to a central processor or other device suitable for continuously calculating the density of the flowing fluid.